This work investigated the transformation of triclosan （TCS） by the laccase produced by a pathogen isolated from rotten tomato. The pathogen was characterized as Bot^tis sp. FQ, belonging to subphylum Deuteromw＇oti...This work investigated the transformation of triclosan （TCS） by the laccase produced by a pathogen isolated from rotten tomato. The pathogen was characterized as Bot^tis sp. FQ, belonging to subphylum Deuteromw＇otina. The laccase exhibited cold-adaptation with relatively high activity at 20℃. The laccase could effectively transform TCS. Approximately 62% TCS could be removed at dose of 1.0 unit·mL^-1 in 120min. The reaction rate appeared to be pseudo-first-order to the concentration of the substrate, suggesting the laccase activity remained stable during the reaction. Transformation products of TCS were analyzed by mass spectrometry and it was revealed that TCS dimers were formed via radical coupling pathways. During this process, laccase catalyzed oxidation of TCS to form a radical intermediate is the rate limiting step. However, this step can be reversed by humic acid. Overall, the laccase showed great potential in the treatment of phenolic contaminants. Since laccase is widely presented in natural environment, this study also revealed an important pathway involved in the transformation of phenolic contaminants in the environment.展开更多
文摘This work investigated the transformation of triclosan （TCS） by the laccase produced by a pathogen isolated from rotten tomato. The pathogen was characterized as Bot^tis sp. FQ, belonging to subphylum Deuteromw＇otina. The laccase exhibited cold-adaptation with relatively high activity at 20℃. The laccase could effectively transform TCS. Approximately 62% TCS could be removed at dose of 1.0 unit·mL^-1 in 120min. The reaction rate appeared to be pseudo-first-order to the concentration of the substrate, suggesting the laccase activity remained stable during the reaction. Transformation products of TCS were analyzed by mass spectrometry and it was revealed that TCS dimers were formed via radical coupling pathways. During this process, laccase catalyzed oxidation of TCS to form a radical intermediate is the rate limiting step. However, this step can be reversed by humic acid. Overall, the laccase showed great potential in the treatment of phenolic contaminants. Since laccase is widely presented in natural environment, this study also revealed an important pathway involved in the transformation of phenolic contaminants in the environment.
